Reserve 1/2 cup crumbled cookies and 1/4 cup marshmallows. Line an 8x8x2-inch baking pan with foil, leaving a few inches on each end to use as handles. Spray the foil with vegetable cooking spray.Heat the chocolate pieces, condensed milk and salt in a 2-quart saucepan over low heat until the chocolate is melted and the mixture is smooth, stirring often.Remove the saucepan from the heat.  Stir in the remaining crumbled cookies, marshmallows and the vanilla extract. Spread the chocolate mixture in the pan.  Press the reserved crumbled cookies and marshmallows into the top.Refrigerate for 2 hours or until firm.  Remove the fudge from the pan using the foil handles and peel away the foil.  Cut into 16 squares.  Store in the refrigerator in a covered container.